Rockwell Automation 1775-S4B,D17756.5.3 User Manual SCANNER/MSG HND - Manual (Page 121)

Using Commands in Report Generation
Chapter 10
10Ć18
Statement Function
=
==
=?
==?
Assigns the numeric value on the right to the variable or address
on the left. If a user symbol is on the left, it is defined to be a
procedural symbol.
Example: A = 10
Assigns the numeric value on the right to the variable or address
on the left. If a user symbol is on the left, it is defined as an
interprocedural symbol.
Example: B == 100
Assigns the string value on the right to the variable or address on
the left. Only a user symbol can appear on the left side of a
string assignment.
Example: CHAR =? `ENTER A CHARACTER'
Assigns the string value on the right to the variable on the left. If
a user symbol is on the left, it is defined as an interprocedural
symbol.
Example: CHAR ==? `ENTER TEMPERATURE READING'
Refer to chapter 8 for a discussion on these assignment statements.
The source for a value depends upon what the value is. If the value is a
string, the source can be:
Direct string value
User symbol
If the value is a number, the source can be:
Direct numeric value
Value at a logical address
Value at a symbolic address
Value of an expression
Value of a user symbol
When the 1775-S4B scanner reads an assignment statement, it reads the
data from the right side of the assignment statement to the left side. Thus,
the source data moves to the destination data.
You can use the assignment statement for two purposes:
Instruct the 1775-S4B scanner to execute a data table read
Instruct the 1775-S4B scanner to execute a data table write
A data table read copies information from the data table to the destination.
A data table write copies information from a source into the data table.